Apparatus for the display of illuminated translucent documents

Abstract

A device for a front lit illuminated panel for the directional illuminated of a display surface having at least one luminous source emitting a light flux which penetrates into a plate of transparent material and exits after encountering striations whose depth increases as a viewer observing the display moves away from the light source lighting the field of the plate. The individual striations are distributed along lines parallel to the lighted field of the plate, while being spaced from one another on each line. The length of the increased striations along their respective lines increase and the space along the same line, between individual striations, decrease as a viewer observing the display moves away from the light source.

I claim: 
     
       1. In a front lit illuminated panel for directional illumination of a translucent display, comprising: at least one light source emitting a light flux;   a plate of transparent material including striations and having light re-emitting elements, said light re-emitting elements re-emitting flux meeting said elements from said at least one light source and exiting from said plate of transparent material to light said display;   said light re-emitting elements in said plate being arranged and/or distributed in such a way that their light re-emitting power increases as the distance away from the light source increases; and   said plate having on at least one of its front and back surfaces striations whose depth increases in a direction as the distance away from said light source increases; and wherein   the improvement consists essentially in that said striations are individual and distributed along lines parallel to a lighted field of the plate and spaced from one another on each of said lines, the length (l) of said striations along the respective lines increasing and the space (a) along the same line between said individual striations decreasing in the direction away from a viewer observing said display.   
     
     
       2. The device according to claim 1, wherein said individual striations are dephased with respect to one another, from one line of striations to the next. 
     
     
       3. The device according to claim 2, wherein said light re-emitting elements are constituted by inserts, said inserts being distributed in said plate in such a way that their density increases from said light source towards the plane of symmetry (p) of the device. 
     
     
       4. The device according to claim 2, also having individual striations similarly arranged on the front and on the rear surface of said plate. 
     
     
       5. The device according to claim 4, comprising an intermediate light source and two outer light sources, said intermediate light source being parallel to said outer light sources and housed in a groove formed in the front or rear surface of said plate, said individual striations being distributed symmetrically relative to two horizontal planes located, respectively, midway between said intermediate light source and said outer light source. 
     
     
       6. The device according to claim 5, further having a translucent screen mounted in front of said intermediate light source. 
     
     
       7. The device according to claim 1, wherein said light re-emitting elements are constituted by inserts, said inserts being distributed in said plate in such a way that their density increases from said light source toward the plane of symmetry (p) of the device. 
     
     
       8. The device of claim 7, wherein said inserts consist of microspheres or microbubbles. 
     
     
       9. The device according to claim 7, comprising an intermediate light source and two outer light sources, said intermediate light source being parallel to said outer light sources and housed in a groove formed in the front or rear surface of said plate, said individual striations being distributed symmetrically relative to two horizontal planes located, respectively, midway between said intermediate light source and said outer light sources. 
     
     
       10. The device according to claim 9, further having a translucent screen mounted in front of said intermediate light source. 
     
     
       11. The device according to claim 4, also having individual striations similarly arranged on the front and on the rear surface of said plate. 
     
     
       12. In a front lit panel as claimed in claim 1, having at least two light sources and said plate of transparent material having a central plane of symmetry and said light sources being placed at opposite ends of said plate from said central plane of symmetry, and wherein the length of said striations along their respective lines increases as the distance increases from the respective said light source towards said central plane of symmetry and the horizontal space (a) along the same line between said individual striations decreases in that direction. 
     
     
       13. A front lit illuminated panel for directional illumination of a translucent display, comprising: at least one light source;   a plate of transparent material having light re-emitting elements;   said light source emitting flux meeting said re-emitting elements and exiting from said plate to light said translucent display through said plate of transparent material;   said light re-emitting elements being distributed in the plate such that their light re-emitting power increases as the distance away from the light source increases;   said plate having, on at least one of its front and back surfaces, striations whose depth increases in a direction as the distance away from said light source increases; and   said striations are individual and are distributed along lines parallel to the lighted field of the plate and spaced from one another on each of said lines, the length (l) of said striations along the respective lines increasing and the space (a) along the same line between said individual striations decreasing in the direction away from a viewer observing said display.   
     
     
       14. The panel of claim 13, wherein the striations have a depth p which increases in the direction of a plane of symmetry of said plate of transparent material. 
     
     
       15. The panel of claim 14, including two light sources, one at each end of said plate of transparent material. 
     
     
       16. The panel of claim 15, wherein said plate of transparent material has a central plane of symmetry, and the length of said striations along their respective lines increases as the distance increases from said light source towards said central plane of symmetry and the horizontal space (a) along the same line between said individual striations decreases in that direction. 
     
     
       17. The panel of claim 13, including two light sources, one at each end of said plate of transparent material. 
     
     
       18. The panel of claim 13, wherein said plate of transparent material has a centrl plane of symmetry, and the length of said striations along their respective lines increases as the distance increases from said light source towards said central plane of symmetry and the horizontal space (a) along the same line between said individual striations decreases in that direction.